Substrate processing system and state monitoring method

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2020-147364, filed on Sep. 2, 2020, the entire contents of which are incorporated herein by reference.

The present disclosure relates to a substrate processing system and a state monitoring method.

Patent Document 1 discloses a measurement system for measuring an amount of a focus ring consumed in a plasma etching apparatus including a processing container, a placement stage, and the focus ring. The measurement system includes a sensor board provided with a distance sensor and a measurement device configured to measure the consumption amount of the focus ring. In this system, the measurement device includes a transfer instruction part configured to instruct a transfer apparatus to transfer the measurement device into the processing container, an acquisition part configured to acquire physical quantity information according to a distance from the distance sensor to the focus ring measured by the distance sensor, and a measurement part configured to measure the consumption of the focus ring on the basis of the acquired physical quantity information.

According to one embodiment of the present disclosure, there is provided a substrate processing system including a substrate processing apparatus configured to process a substrate, a substrate transfer mechanism including a substrate holder configured to hold the substrate, the substrate transfer mechanism being configured to hold the substrate on the substrate holder and to load and unload the substrate into and out of the substrate processing apparatus, an imaging device provided in the substrate transfer mechanism and configured to image a monitoring target member inside the substrate processing apparatus, and a controller. The controller is configured to cause the imaging device to image multiple portions of the monitoring target member, including a central portion facing a center of the substrate during processing and a peripheral edge portion facing a peripheral edge side of the substrate during the processing, by moving the substrate holder, and calculate, for each of the multiple portions of the monitoring target member, a physical amount indicating a state of the corresponding portion based on an imaging result.

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.

For example, in a process of manufacturing a semiconductor device or the like, a predetermined process, such as a film forming process or an etching process, is performed on a substrate such as a semiconductor wafer (hereinafter, referred to as a “wafer”) by a substrate processing apparatus.

The state of a member inside this substrate processing apparatus changes as the above-mentioned processes are repeated. For example, in a substrate processing apparatus that performs an etching process, a shower head provided with a plurality of ejection holes for ejecting a processing gas towards a substrate is provided so as to face the substrate. However, since the ejection holes are also etched by the etching process performed on the substrate, the diameter of the ejection holes gradually increases. In addition, when inside of the substrate processing apparatus is exposed to an air atmosphere in order to check a state of each member inside the substrate processing apparatus, it takes a long time to return the inside of the substrate processing apparatus to a vacuum atmosphere.

In relation to this point, Patent Document 1 discloses a method of measuring the consumption amount of the focus ring provided inside the processing container of a plasma etching apparatus using a sensor board provided with a distance sensor.

The change in the state of a member inside the substrate processing apparatus due to the repetition of a predetermined process, such as an etching process, differs between the central portion facing the center of the substrate and the peripheral portion facing the peripheral edge side of the substrate during a predetermined process. For example, when an etching process using plasma is performed, the plasma density above the center of the substrate may be high and the plasma density above the peripheral edge side of the substrate may be low. In this case, the etching amount of the processing gas ejection holes is larger at the central portion of the shower head than at the peripheral edge portion. Therefore, regarding a member inside the substrate processing apparatus, an appropriate result may not be obtained when the state of only a portion facing a part of the substrate in the radial direction is monitored and on the basis of the monitoring results, the time for replacement of the member is determined or processing conditions are adjusted.

Therefore, with the technique according to the present disclosure, an appropriate result is obtained when determining the time for replacement of the above-mentioned member or the like on the basis of a monitoring result, even when the state of the member differs between the central portion and the peripheral portion in the case in which the state of the member is monitored without exposing the inside of the substrate processing apparatus to an air atmosphere.

Hereinafter, a substrate processing system and a state monitoring method according to the present embodiment will be described with reference to the drawings. In the specification and drawings, elements having substantially the same functional configurations will be denoted by the same reference numerals and redundant descriptions will be omitted.

is a plan view illustrating a schematic configuration of a wafer processing systemas a substrate processing system according to an embodiment.

The wafer processing systemofperforms a predetermined process, such as a film forming process, a diffusion process, or an etching process on a wafer W as a substrate under a reduced pressure. The wafer processing systemhas a configuration in which a carrier stationin which a carrier C capable of accommodating a plurality of wafers W is loaded and unloaded and a processing stationincluding a plurality of various processing modules, each of which is configured to perform a predetermined process on a wafer W under a reduced pressure, are integrally connected with each other. The carrier stationand the processing stationare connected via two load-lock apparatusesand.

The load-lock apparatusesandhave respective load-lock chambersandconfigured to switch the interiors thereof between an atmospheric pressure state and a vacuum state. The load-lock apparatusesandare provided so as to connect an atmospheric transfer apparatusand a vacuum transfer apparatus, which will be described later.

The carrier stationincludes the atmospheric transfer apparatusand a carrier placement stage. The carrier stationmay be further provided with an orienter (not illustrated) configured to adjust the orientation of the wafers W.

The atmospheric transfer apparatusincludes a housing that forms an atmospheric transfer chamber, the interior of which is under an atmospheric pressure. The atmospheric transfer chamberis connected to the load-lock chambersandof the load-lock apparatusesandvia gate valves Gand G. A transfer mechanismis provided in the atmospheric transfer chamberto transfer the wafers W between the load-lock chambersandand the atmospheric transfer chamberunder the atmospheric pressure.

The transfer mechanismincludes a transfer arm, and the transfer armis configured as, for example, an articulated arm provided with a wafer holding part configured to hold a wafer W at the tip end thereof. The transfer mechanismis configured to transfer a wafer W while holding the wafer W using the transfer arm

The carrier placement stageis provided on a side surface of the atmospheric transfer apparatusopposite to the load-lock apparatusesand. In the illustrated example, the carrier placement stageis configured such that a plurality of (e.g., three) carriers C can be placed thereon. The wafers W in the carriers C placed on the carrier placement stageare loaded and unloaded into and out of the atmospheric transfer chamberby the transfer armsof the transfer mechanismof the atmospheric transfer apparatus.

The processing stationincludes a vacuum transfer apparatusand processing apparatusesto.

The vacuum transfer apparatushas a vacuum transfer chamber, the interior of which is maintained at a reduced pressure state (a vacuum state). The vacuum transfer chamberis configured as a housing that is sealable, and is formed so as to have, for example, a substantially polygonal shape (a hexagonal shape in the illustrated example) in a plan view. The vacuum transfer chamberis connected to the load-lock chambersandof the load-lock apparatusesandvia the gate valves Gand G. In the vacuum transfer chamber, a wafer transfer mechanismas a substrate transfer mechanism is provided to transfer wafers W between vacuum processing chambersto(described later) of the processing apparatusesto. The wafer transfer mechanismincludes a transfer arm. Details of the configuration of the wafer transfer mechanismwill be described later.

Outside the vacuum transfer chamberof the vacuum transfer apparatus, the processing apparatusestoas substrate processing apparatuses and load-lock apparatusesandare arranged so as to surround the vacuum transfer chamber. The load-lock apparatus, the processing apparatusesto, and the load-lock apparatusare arranged in this order in the clockwise rotation direction in a plan view from, for example, the load-lock apparatus, and to face respective side surface portions of the vacuum transfer chamber.

Each of the processing apparatusestoperforms a predetermined process, such as a film forming process, a diffusion process, or an etching process, on a wafer W under a reduced pressure. In the present embodiment, it is assumed that the processing apparatusestoperform an etching process using plasma. The processing apparatusestohave respective vacuum processing chambersto, inside each of which an etching process is performed on a wafer W under a reduced pressure. The vacuum processing chamberstoare connected to the vacuum transfer chamberof the vacuum transfer apparatusvia gate valves Gto G, respectively. Details of the configuration of the processing apparatuswill be described later. Since the configurations of the processing apparatusestoare the same as that of the processing apparatus, description of the details thereof will be omitted.

In addition, the wafer processing systemincludes a controller. The controllercomprises, for example, a computer including a CPU, a memory, or the like, and includes a program storage (not illustrated). The program storage stores a program for controlling the wafer processing in the wafer processing systemand a program for monitoring a state inside of each of the processing apparatusesto. The program may be recorded in a computer-readable storage medium, and may be installed in the controllerfrom the storage medium. Some or all of the programs may be implemented by dedicated hardware (a circuit board).

Next, a processing apparatuswill be described with reference to.is a vertical cross-sectional view illustrating a schematic configuration of the processing apparatus.is a partially enlarged cross-sectional view of an electrostatic chuck to be described later.

As illustrated in, the processing apparatusincludes a processing container, a gas supplier, a radio frequency (RF) power supply, and an exhaust system. In addition, the processing apparatusincludes a support baseand a shower head.

The processing containeris a container, inside of which is configured to be decompressed, and constitutes a vacuum processing chamber. The processing containerhas, for example, a substantially cylindrical shape. A side wall of the processing containeris provided with a loading and unloading portof wafers W, and the loading and unloading portis provided with a gate valve Gconfigured to open and close the loading and unloading port

The support baseis disposed in a lower region of a plasma processing spacewithin the processing container. The shower headis disposed above the support baseand serves as a part of a ceiling of the processing container.

The support baseis configured to support a wafer W in the plasma processing space. The support baseincludes a lower electrode, an electrostatic chuckserving as an attractive holding member, an insulator, and a lifting pin.

The lower electrodeis made of a conductive material such as aluminum.

The electrostatic chuckis provided on the lower electrodeand attracts and holds a wafer W by an electrostatic force. The electrostatic chuckincludes, at the center thereof, a placement portionon a top surface of which a wafer W is placed. In the electrostatic chuck, the top surface of the placement portionis formed to be higher than a top surface of an outer peripheral portion of the electrostatic chuck. A focus ringis mounted on the top surface of the outer peripheral portion surrounding the placement portionof the electrostatic chuck.

The focus ringis an annular member disposed so as to surround the wafer W mounted on the placement portionof the electrostatic chuck, and improves, for example, uniformity of a plasma process (a plasma etching process in this example). The focus ringis formed of a material appropriately selected according to the plasma process to be performed, and is formed of, for example, silicon.

The placement portionis provided with an electrodeconfigured to hold a wafer W through electrostatic attraction. The electrostatic chuckhas a configuration in which the electrodeis sandwiched between insulating materials. A DC voltage from a DC power supply (not illustrated) is applied to the electrode. Due to the electrostatic force generated thereby, a wafer W is attracted and held on the top surface of the placement portionof the electrostatic chuck.

In the present embodiment, the placement portionof the electrostatic chuckon which a wafer W is placed and the portion on which the focus ringis mounted are integrated, but these may be separate bodies.

The top surface of the placement portionof the electrostatic chuckis formed to have, for example, a diameter smaller than the diameter of the wafer W, and when the wafer W is placed on the top surface of the placement portion, a peripheral edge of the wafer W protrudes from the placement portion. Further, the focus ringhas a step formed on the upper portion thereof, so that the top surface of the outer peripheral portion thereof is formed to be higher than the top surface of the inner peripheral portion thereof. The focus ringis formed such that the inner peripheral portion thereof is introduced below the peripheral edge of the wafer W protruding from the placement portion. That is, the inner diameter of the focus ringis formed to be smaller than the outer diameter of the wafer W.

In addition, below the electrodein the electrostatic chuck, a heateras a temperature adjustment mechanism for adjusting a temperature of the wafer W is embedded. The heaterheats the wafer W held by the electrostatic chuckby heating the electrostatic chuck. The heateris configured such that the temperature of each of multiple regions in the radial direction of the wafer W is independently adjustable. Specifically, the heaterincludes, for example, a heater configured to heat a region at the center of the electrostatic chuckin a plan view, and heaters configured to independently heat multiple respective annular regions arranged in order from a region at the center of the electrostatic chuckin the plan view towards outside in the radial direction of the electrostatic chuck.

In addition, as illustrated in, a plurality of convex portionsare provided on the top surface of the placement portionof the electrostatic chuck, for example, at equal intervals. This is to prevent the wafer W from being continuously attracted by the electrostatic chuckdue to a residual attractive force when the voltage application to the electrodeis stopped. The convex portionsare formed in a columnar shape having, for example, a diameter of 300 μm to 500 μm and a height of 5 μm to 30 μm.

As illustrated in, the insulatorsupports the lower electrode. The insulatoris, for example, a cylindrical member having an outer diameter equivalent to the outer diameter of the lower electrode, and is made of ceramic or the like to support the peripheral edge side of the lower electrode.

The lifting pinis a columnar member that is raised and lowered so as to protrude or retract from the top surface of the placement portionof the electrostatic chuck, and is formed of, for example, ceramic. Three or more lifting pinsare provided at intervals from each other in the circumferential direction of the electrostatic chuck, specifically, the circumferential direction of the top surface of the placement portion

The lifting pinsare connected to a lifting mechanismthat raises and lowers the lifting pins. The lifting mechanismincludes, for example, a support memberconfigured to support the plurality of lifting pins, and a driving mechanismconfigured to generate a driving force for lifting and lowering the support memberso as to raise and lower the plurality of lifting pins. The driving mechanismincludes an actuator such as a motor that generates a driving force.

The lifting pinsare inserted into respective through holesextending downwards from the placement portion of the electrostatic chuckto the bottom surface of the lower electrode. The upper end surfaces of the lifting pinssupport the rear surface of the wafer W when the lifting pinsare raised.

The shower headserves as an upper electrode, and also functions as a shower head that supplies a processing gas from the gas supplierto the plasma processing space. The shower headincludes an electrode platedisposed so as to face the inside of the processing containerand a supportprovided above the electrode plate. In addition, the shower headis supported in the upper portion of the processing containervia an insulative blocking member.

A plurality of ejection holesare formed in the electrode plate, for example, at equal intervals. The ejection holeseject a processing gas or the like into the plasma processing space. Specifically, the ejection holeseject the processing gas towards the wafer W that is attracted to and held by the electrostatic chuckduring the plasma etching process. In addition, the ejection holeseject a cleaning gas towards the electrostatic chuckduring cleaning of the processing apparatus. The electrode plateis formed of, for example, silicon.

The supportdetachably supports the electrode plate, and is formed of a conductive material such as aluminum. A gas diffusion chamberis formed inside the support. A plurality of gas flow holescommunicating with the ejection holesare formed from the gas diffusion chamber

The gas supplierincludes one or more gas supply sourcesand one or more flow rate controllers. The gas suppliersupplies, for example, one or more processing gases or one or more cleaning gases from respective corresponding gas supply sourcesto the gas diffusion chambervia respective corresponding flow rate controllers. Each flow rate controlleris, for example, a pressure control type flow rate controller.

In the processing apparatus, a processing gas from a gas supply sourceselected from one or more gas supply sourcesis supplied to the gas diffusion chambervia the flow rate controller. Then, the processing gas supplied to the gas diffusion chamberis dispersed and supplied in the form of a shower in the plasma processing spacevia the gas flow holesand the ejection holes

The processing apparatusis configured such that a supply flow rate of the processing gas from the shower headis independently adjustable in each of a plurality of regions extending in the radial direction of the wafer W. For example, in the processing apparatus, although not illustrated, the gas diffusion chamberis divided into three or more in the radial direction, and the gas diffusion chambersadjacent to each other are separated by a partition wall. Thus, the pressure of the processing gas supplied from the gas supplierto each gas diffusion chamberis individually adjustable.

The RF power supplyincludes, for example, two RF generatorsandand two matching circuitsand. The RF generatorand the RF generatorare connected to the lower electrodevia the matching circuitsand, respectively, and supply RF power to the lower electrode.

The RF generatorgenerates and supplies RF power for plasma generation. The frequency of the RF power from the RF generatoris, for example, 27 MHz to 100 MHz. The matching circuithas a circuit for matching an output impedance of the RF generatorwith an input impedance on the load (the lower electrode) side.

The RF generatorgenerates and supplies RF power for drawing ions into the wafer W (high-frequency bias power). The frequency of the RF power from the RF generatoris, for example, 400 kHz to 13.56 MHz. The matching circuithas a circuit for matching the output impedance of the RF generatorwith the input impedance on the load (the lower electrode) side.